The present invention relates to a keyboard device of an electronic musical instrument and, more particularly, to a structure of a key.
Various types of keyboard devices have been developed to allow a smooth and proper manner of striking or touching the keys of a keyboard instrument and to improve durability thereof. However, these conventional keyboard devices have respective advantages and disadvantages. Only a few keyboard devices are proposed in consideration of operability at the time of assembly or disassembly for a repair.
A typical keyboard device aimed at the smooth touch has a common shaft on which back end portions of the keys are mounted. These keys are aligned to be parallel to each other along a direction perpendicular to the common shaft and can be selectively pivoted about the common shaft. According to this keyboard device, the common shaft must be inserted after all keys are completely aligned. Further, when any one of the keys is to be replaced, the common shaft must be removed from all the keys located outside the key to be replaced, resulting in inconvenience. Such a conventional keyboard device is described in U.S. Pat. No. 3,740,448.
Another conventional keyboard device is proposed wherein support shafts are respectively provided for all keys, and each key has a U-shaped back end portion whose side walls must be expanded outward and mounted on two ends of the corresponding shaft the center of which is fixed. According to this keyboard device, the side walls of the back end portion of each key must be expanded outward, and assembly and disassembly operations are time-consuming and cumbersome. A typical example of the keyboard device of this type is described in Japanese Utility Model Application Disclosure No. 57-60191.